The use of wireless network communication systems that permit hosts to communicate via an optical cable, copper cable, or radio link has become widespread. Hosts are embedded with wireless communication electronics to communicate with other hosts and also to connect to a core network via access points, such as a local area network (LAN) and the Internet. The access point relays network packets between hosts and the core network, and also among hosts.
Hosts and base stations using Open Systems Interconnection (OSI) layer two technologies, such as Ethernet, to communicate with the core network and each other are less efficient at handling broadcast and multicast network packets. One kind of broadcast network packets on Internet Protocol (IP) networks belongs to Address Resolution Protocol (ARP) protocol network packets. For multicast network packets, the Internet Group Management Protocol (IGMP) is one of many communications protocol used by hosts and adjacent routers to establish multicast group memberships.
Due to historical technology development, hosts that belong to the same layer two networks are usually close together and share the same communication channel or the cost of communications with each other is low. Therefore, broadcast and multicast packets in layer two networks have not been a significant concern. When a layer two network is formed through layer three networks, broadcast and multicast packets in the layer two network may become a concern as the amount of packets increases. ARP proxy, proxy server, LAN segmentation, caching are common methods to reduce layer two broadcast and multicast packets.
When layer two packets are encapsulated in layer three packets, for example through Layer Two Tunnelling Protocol (L2TP) and virtual private network (VPN), the amount of broadcast and multicast packets could have a severe negative impact on layer three network performance. Furthermore, when radio spectrum is used to transmit the layer three packets, there may not be enough capacity to transit the broadcast and multicast packets.
Prior arts ARP proxy, proxy server, LAN segmentation, caching and other broadcast and multicast packets reduction techniques do not allow transmission of broadcast and multicast packets selectively and particularly broadcast and multicast packets originated from a mobile network device through layer three networks.
U.S. Pat. No. 7,356,032 discloses a system and method for reducing broadcast packets among mobile units by using a cache to store Ethernet/IP address pairs in each base station. However, U.S. Pat. No. 7,356,032 cannot reduce broadcast packets if the mobile units are connecting to the core network using OSI layer two protocol through layer three networks. Also U.S. Pat. No. 7,356,032 relies on wireless access point to manage ARP packets. This also increases the complexity of the design of wireless access point.
FIG. 1 illustrates a network environment where communication systems and hosts, such as client computers 111, 112, 113 and 114, communicate to wide area networks (WANs) or the Internet directly. In this particular network environment, those skilled in the art would appreciate that when client computer 111 sends OSI layer three packets to the Internet through the following steps: first, client computer 111 sends OSI layer three packets to wireless access point (AP) 101 (Computer Layer Two Packets) through radio link 121, wherein the layer two packets encapsulate layer three packets from computer 111 (Computer Layer Three Packets); secondly, AP 101 communicates with Tunnel Termination Gateway 104 through interconnected networks, such as Internet 103, by using layer three packets (AP Layer Three Packets) to encapsulate Computer Layer Two Packets; thirdly, Tunnel Termination Gateway 104 decapsulates AP Layer Three Packets to retrieve Computer Layer Two Packets and sends Computer Layer Two Packets to Internet Gateway 106 through private networks 105; finally, Internet Gateway 106 decapsulates Computer Layer Two Packets to retrieve Computer Layer Three Packets and sends Computer Layer Three Packets to Internet 103.
When there are OSI layer three packets for client computer 111 from Internet 103: first, Internet Gateway 106 receives the layer three packets (Internet Packets) from Internet 103 and sends the Internet Packet to Tunnel Termination Gateway 104 by encapsulating Internet Packet in layer two packets (Gateway Layer Two Packets); secondly, Tunnel Termination Gateway 104 encapsulates Gateway Layer Two Packets in layer three packets (Tunneled Layer Three Packets) and sends Tunneled Layer Three Packets to AP 101 through Internet 103; thirdly AP 101 decapsulates Tunnelled Layer Three Packets to retrieve Gateway Layer Two Packets and sends Gateway Layer Two Packets to client computer 111 through radio link 121; finally client computer 111 retrieves Internet Packets by decapsulating Internet Packets from Gateway Layer Two Packets.
AP 101 and Tunnel Termination Gateway 104 are connected through a layer two tunnel by using layer three packets. The layer two tunnel may be implemented by using L2TP or other tunnelling protocols. Myriad other combinations and permutations of how to establish a layer two tunnel between two communication systems using layer three packets would be appreciated by those of ordinary skill given the present disclosure.
The steps of communicating with Internet 103 by client computer 112 are similar to the steps of communicating with Internet 103 by client computer 111. The same steps are applied to computing devices 113 and 114, however instead of using AP 101, AP 102 is used. It is apparent to a skilled person in the art how the steps of communicating with Internet 103 also apply to hosts, client computers, computing devices and communication systems through wireless access points, Tunnel Termination Gateway 104, private networks 105 and Internet Gateway 106.
It may be noted that server 115 and client computers 111, 112, 113 and 114 all belong to the same layer two network as they are connected through layer three networks between AP 101 and Tunnel Termination Gateway 104 and between AP 102 and Tunnel Termination Gateway 104. Therefore, when server 115 sends a layer two broadcast or multicast packet, the broadcast or multicast packet is then duplicated by Tunnel Termination Gateway 104, AP 101 and AP 102 and sent to client computers 111, 112, 113 and 114. This type of broadcast or multicast network packets may easily consume a significant part of network resources between AP 101 and Internet 103, between AP 102 and Internet 103, between Tunnel Termination Gateway 104 and Internet 103, radio spectrum of AP 101 and radio spectrum AP 102. This invention aims to reduce broadcast and multicast network packets in the network environment just described.